Lightweight Directory Access Protocol (LDAP) is an Internet protocol that enables users with LDAP clients to access directory information from the Microsoft Exchange Server directory. Client with permission to use LDAP can browse, read, search, and write directory listings in the Exchange directory.

1. In the Exchange Advanced tab, click Protocol Settings. The Protocols dialog box is displayed.
2. Click LDAP (Lightweight Directory), and then click Settings. The LDAP Protocol Details dialog box is displayed.
3. To enable the protocol for this mailbox, select the Enable for mailbox check box. To disable the protocol for this mailbox or contact, click to clear the Enable for mailbox check box.
4. To use LDAP protocol defaults for MIME encoding, default character set, rich-text format, public folders, fast message retrieval and user delegation, select the Use protocol defaults check box. When selected, all remaining options in the LDAP Protocol Details dialog box are unavailable (grey). To use settings other than the default, click to clear the Use protocol defaults check box.